Magnetocrystalline Anisotropy of Single-Crystal Europium Oxide

Abstract

The first-order cubic anisotropy constant ${K}_{1}$ in EuO single crystal was measured as a function of temperature and applied field by the static torque method. The value at $T=0\ifmmode^\circ\else\textdegree\fi{}$K is ${K}_{1}(0)=\ensuremath{-}(4.36\ifmmode\pm\else\textpm\fi{}0.1)\ifmmode\times\else\texttimes\fi{}{10}^{5}$ erg/${\mathrm{cm}}^{3}$. The variation of ${K}_{1}$ with $T$ and $H$ is uniquely described by the behavior of the measured magnetic moment $\ensuremath{\sigma}(H, T)$. The observed relationship between $\frac{{K}_{1}(H, T)}{{K}_{1}(0, 0)}$ and $\frac{\ensuremath{\sigma}(H, T)}{\ensuremath{\sigma}(0, 0)}$ is explained by a theory of single-ion interaction with the cubic crystal potential. The cubic crystal-field splitting parameter ${b}_{4}=(21.2\ifmmode\pm\else\textpm\fi{}0.5)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$ ${\mathrm{cm}}^{\ensuremath{-}1}$/ion obtained from ${K}_{1}(0)$ is compared with results for ${\mathrm{Eu}}^{++}$ ions in various other materials.